It's a long way to drive unless you're going to San Diego anyway, but the outlet at Las American mall in San Ysidro (south of San Diego at the Mexican border) has a corner with parks merchandise. Usually one or two wall to ceiling section of shelves, and 1-4 racks of clothes. I don't think there is any schedule to what they have out at any given time.
It's a nice outlet mall if you're in the area.